Torquespeed

Torquespeed is a descriptive term used to discuss the relationship between torque and rotational speed in a motor or rotating system. In steady operation, mechanical power is the product of torque and angular speed (P = T · ω), allowing a direct link between how hard a motor can turn and how fast it spins under load.

Most electric motors exhibit a characteristic torquespeed curve. At zero speed, the motor can produce its maximum stall torque, while at zero torque the speed reaches a no-load value. In many DC motors, torque varies roughly linearly with current, and speed varies roughly linearly with applied voltage. As load torque rises, speed falls accordingly because the motor must deliver the opposing torque while balancing power output and losses.

Maximum mechanical power typically occurs at an intermediate point on the curve, where torque and speed are both substantial but not at their extreme values. Beyond this point, increasing torque further reduces speed and the net power delivered drops.

Control and design considerations include methods to shape the torquespeed relationship. Speed control is often achieved by adjusting voltage or current, using PWM, and implementing feedback control loops to maintain a target speed under varying loads. Different motor types (DC brushed, brushless DC, and AC induction) have distinct torquespeed characteristics and slip behavior, especially under load.

Applications frequently use gear trains to modify the torquespeed outcome at the load: output torque scales with the gear ratio (minus losses), while output speed is reduced by the same ratio. The torquespeed relationship remains central to selecting motors, drives, and control strategies for efficient and responsive systems.